Idylls of the Rat King is not an AFF adventure module set in Allansia, but it is a dungeon crawl for another ruleset and another world. However, it starts from a town called Silverton, that was once a minerary town (mining silver, of course, with that name...) and only later on, when the the mine closed, it turned to other businesses (like trading, for example...)
As this background story can be remarkably easily adapted to the Allansian Silverton that we all know (the merchant town where The City of Thieves start!) I thught about converting this dungeon crawl to AFF + Allansia... and I think it is reasonably straightforward.
Just in case yoou need something quick and easy to adapt, this may be a good option.

He's a real Nowhere man, sitting in his Nowhere land, making all his Nowhere plans for Nobody.